More dark details have emerged about Celtics guard Jabari Bird’s domestic violence charge. Bird’s girlfriend told police he choked her roughly a dozen times during an argument Friday while kicking her and holding her against her will, according to prosecutors. The woman said Bird’s physical assault caused her to suffer mental distress.

Bird, 24, was arraigned at Brighton Municipal Court on charges of assault and kidnapping. His lawyers pleaded not-guilty on his behalf and he is being held on $50,000 bail, the Boston Globe reports.

At the arraignment, one of Bird’s attorneys, Brian T. Kelly, said there are “always two sides” to incidents, but acknowledged his client understands the “seriousness of the allegations.”

According to police, Bird choked his girlfriend with two hands at least once. At one point during the reported attack, he collapsed and fell to the floor. Bird is currently being held at an unidentified hospital in the Greater Boston area. His girlfriend was transferred to a city hospital as well.

In a statement, the Celtics expressed sympathy towards the victim, and said they are helping authorities with the investigation.

“Most importantly, our thoughts are with the victim of this incident,” the statement reads. “The Celtics organization deplores domestic violence of any kind, and we are deeply disturbed by the allegations against Jabari Bird. Pursuant to Domestic Violence Policy in the NBA’s labor agreement, matters of this kind are handled by the League Office, not the team, and so the Celtics will be working with both the league and local authorities to assist in their ongoing investigations. The team will have no further comment at this time.”

The Celtics selected Bird with the No. 56 overall pick in the 2017 NBA Draft. He played his college ball at the University of California Berkeley.